The present invention relates to a deflection yoke for use in a color television receiver set, specifically a deflection yoke adapted to adjust a deflection current which flows in a horizontal deflection coil and generates a desired deflection field.
Generally, in a color television receiver set which employs an in-line type cathode-ray tube or a delta type cathode-ray tube, pictures are provided by electron guns which produce red, green and blue electron beams. In this case, the deflection yoke is mounted on a neck of the cathode-ray tube to converge electron beams on the screen surface. The deflection yoke is constituted to obtain an optimum self-convergence by appropriately setting a horizontal deflection field and a vertial deflection field.
However, the deflection coil comprises a horizontal deflection coil, a vertical deflection coil and a core. Once the deflection coil is fabricated, it is difficult to adjust a variation of unallowable manufacturing error which is found after fabrication and, similarly, once the cathode-ray tube is fabricated, it is also difficult to adjust a variation of unallowable manufacturing error which is found after manufacture. To adjust such variation of unallowable manufacturing error of the deflection yoke or the cathode-ray tube, a convergence yoke is employed or a magnetic piece or a piece of magnet is attached to the deflection yoke.
However, the use of the convergence yoke is disadvantageous in that not only the adjustment of concentration of electron beams is complicated but the costs of the deflection circuitry which includes the deflection yoke are increased. The use of the magnetic piece or a piece of magnet is also disadvantageous in that the range of adjustment is limited to a local field, readjustment cannot be freely carried out and the accuracy after adjustment is not satisfactory. Particularly, the display of character information on the screen is required to provide only an extremely small misconvergence. The above-mentioned measures cannot provide a substantial effect to eliminate misconvergence.
The coils which were wound to obtain an optimum field cannot always provide the optimum field due to restrictions in manufacture and construction and therefore there have been a problem that the coils should be designed with a certain degree of misconvergence left, that is, a problem of a remainder of design.
An object of the present invention is to provide a deflection yoke adapted to obtain a desired deflection field by correcting the distribution of the deflection field generated from the horizontal deflection coil through adjustment of the quantity of current flowing in the coil by the deflection current regulator.
Another object of the present invention is to provide a deflection yoke adapted to generate the deflection field which permits self-convergence by varying the horizontal deflection current flowing in the horizontal deflection coil through the deflection current regulator.
The deflection yoke in accordance with the present invention is provided with a pair of horizontal deflection coils, a pair of vertical deflection coils and a deflection core. The horizontal deflection coil comprises two horizontal coil sections across which a current regulator is connected to allow differential adjustment of horizontal deflection current which flows in these horizontal coil sections.
The horizontal coil sections have two windings which extend in the direction of the axis of cathode-ray tube along the neck of the cathode-ray tube. The winding of one of horizontal coil sections has a conductor distribution of dispersed winding and the winding of the other horizontal coil section has a conductor distribution of concentrated winding, or the winding of one of two horizontal coil sections has a conductor distribution of dispersed winding and the other winding of the other of two horizontal coil sections has a conductor distribution of concentrated winding.